Allow customers to view historical GitLab Duo assignments

Background

Today, there is no way for customers to view historical GitLab Duo assignments.

One customer requested this, as they lost prior seat assignments when they upgraded from GitLab Duo Pro to GitLab Duo Enterprise (note: since then, we have implemented functionality that supports persisting of seat assignments during an upgrade).

Proposal

Provide a means for customers to be able to see historical data for GitLab Duo seat assignments.

Possible limitations: do we keep historical data for this? is there a way to log this?

Result

Customers have visibility into historical assignment data for GitLab Duo.